Help me out here. What am I doing wrong?

I think i'm giving off bad signs to people which is not at all surprising seeing as though I have anxiety. The problem is, there tends to be ONE person in my immediate group whether it be school or at work who HATE me. I'm not exaggerating either..

In my last job, I had to leave because there was THIS person who basically hounded me out. Got very belligerent, very hostile, refused to share information or include in work related matters and unfortunately, the manner himself also colluded with her.

It was great when I finally left but unfortunately a similar situation has happened in my current role. Once again everyone is lovely but there's this one prized *****. She is HORRIBLE.. absolutely detests me so i'm worried this is becoming a bit of a running theme but I honestly don't know what i'm doing wrong.

These people don't just dislike me, they DETEST me.

What can I do?